Data centers housing significant numbers of interconnected computing systems have become commonplace, such as private data centers that are operated by and on behalf of a single organization, and public data centers that are operated by entities as businesses to provide computing resources to customers. For example, some public data center operators provide network access, power, and secure installation facilities for hardware owned by various customers, while other public data center operators provide “full service” facilities that also include hardware resources made available for use by their customers. However, as the scale and scope of typical data centers has increased, the task of provisioning, administering, and managing the physical computing resources has become increasingly complicated.
The advent of virtualization technologies for commodity hardware has provided a partial solution to the problem of managing large-scale computing resources for many customers with diverse needs, allowing various computing resources to be efficiently and securely shared between multiple customers. For example, virtualization technologies such as those provided by VMWare, XEN, or User-Mode Linux may allow a single physical computing machine to be shared among multiple users by providing each user with one or more virtual machines hosted by the single physical computing machine. Each such virtual machine may be a software simulation acting as a distinct logical computing system that provides users with the illusion that they are the sole operators and administrators of a given hardware computing resource, while also providing application isolation and security among the various virtual machines. Furthermore, some virtualization technologies are capable of providing virtual resources that span one or more physical resources, such as a single virtual machine with multiple virtual processors that actually spans multiple distinct physical computing systems.
In addition, various mechanisms exist to allow computers and executing software applications to interact, including to remotely interact with software executing in a data center. For example, remote procedure call (“RPC”) protocols have long existed that allow a program on one computer to cause a program on another computer to be executed. In a similar manner, various object-oriented architectures such as CORBA (“Common Object Request Broker Architecture”) and DCOM (“Distributed Component Object Model”) provide remote execution capabilities. In addition, various middleware programs have been implemented to connect separate applications (often of distinct types and from unrelated sources) to allow communication. For example, various EDI (“Electronic Data Interchange”) networks exist that provide standard mechanisms to allow a computer system of one user of the network to send data to a computer system of another user of the network.
The widespread popularity of the World Wide Web (“Web”) has provided additional opportunities for computers to inter-communicate. For example, much current Web use involves users interactively requesting Web pages from Web servers (e.g., via Web browser applications executing on user computers) and receiving the requested information in response. In addition, there is also growing use of the Web to support the programmatic interaction of remote applications to exchange information via defined APIs (“application program interfaces”), such as via Web services. Web services allow heterogeneous applications and computers to interact, and can be defined and implemented using a variety of underlying protocols and techniques. For example, some Web service implementations return data in XML (“eXtensible Markup Language”) format using HTTP (“HyperText Transport Protocol”) in response to a Web service invocation request specified as a URI (“Uniform Resource Identifier”), such as a URL (“Uniform Resource Locator”) that includes a specified operation and one or more query parameters. In other implementations, additional underlying protocols are used for various purposes, such as SOAP (“Simple Object Access Protocol”) for standard message exchange, WSDL (“Web Services Description Language”) for description of service invocations, and UDDI (“Universal Description, Discovery, and Integration service”) for discovery of available services.
While the availability of data centers and virtualization technologies has provided various benefits, various problems still exist. For example, it is often difficult for a user to create and manage the execution of software programs that provide desired functionality at a remote location such as a data center, particularly when the data center uses virtualization technologies.